From: "David A. Black" <dblack@...>
Date: 2005-07-08T19:40:44+09:00
Subject: Re: accessing index inside map

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Hi --

On Fri, 8 Jul 2005, Robert Klemme wrote:

> Pe=F1a, Botp wrote:
>> nobuyoshi nakada [mailto:nobuyoshi.nakada@ge.com] wrote:
>>
>> #> i'd like to double the element values except those loc on
>> #the 2nd and 5th
>> #> indices eg.
>> #
>> #$ ruby -renumerator -e 'p
>> #(1..6).enum_for(:each_with_index).map{|x,i|[2,5].include?(i) ?
>> #x : x*2}'
>> #[2, 4, 3, 8, 10, 6]
>>
>> Hi Nobu,
>>
>> Wow, cool. But my brain is very tiny compared to other rubyist brains.
>>
>> i was hoping for something straight like,
>>
>>> [1,2,3,4,5,6].map{|x,i|[2,5].include?(i) ? x : x*2}
>> =3D>[2, 4, 3, 8, 10, 6]
>>
>> Maybe you can hack one for dumb rubyists like me.
>
> Err, are you kidding?  Enumerator isn't really that difficult - and you
> don't need to modify Hash or other classes.  It's a simple wrapper
> delegating each to each_with_index.  That simple.

I'd still like to see #man_with_index added to Enumerable.


David

--=20
David A. Black
dblack@wobblini.net
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